Denotes HTTP version 1.0 that can be used in the function BEGIN_REQUEST.

HTTP_VERSION_1

VARCHAR2(10)

'HTTP/1.1'

Denotes HTTP version 1.1 that can be used in the function BEGIN_REQUEST.

Table 169-2 UTL_HTTP Constants - Default Ports

Name

Type

Value

Description

DEFAULT_HTTP_PORT

PLS_INTEGER

80

The default TCP/IP port (80) at which a Web server or proxy server listens

DEFAULT_HTTPS_PORT

PLS_INTEGER

443

The default TCP/IP port (443) at which an HTTPS Web server listens

Table 169-3 UTL_HTTP Constants - HTTP 1.1 Status Codes

Name

Type

Value

Description

HTTP_CONTINUE

PLS_INTEGER

100

The client should continue with its request. This interim response is used to inform the client that the initial part of the request has been received and has not yet been rejected by the server.

HTTP_SWITCHING_PROTOCOLS

PLS_INTEGER

101

The server understands and is willing to comply with the client's request, via the Upgrade message header field, for a change in the application protocol being used on this connection. The server will switch protocols to those defined by the response's Upgrade header field immediately after the empty line which terminates the 101 response.

HTTP_OK

PLS_INTEGER

200

The request has succeeded. The information returned with the response is dependent on the method used in the request

HTTP_CREATED CONSTANT

PLS_INTEGER

201

The request has been fulfilled and resulted in a new resource being created.

HTTP_ACCEPTED

PLS_INTEGER

202

The request has been accepted for processing, but the processing has not been completed. The request might or might not eventually be acted upon, as it might be disallowed when processing actually takes place.

HTTP_NON_AUTHORITATIVE_INFO

PLS_INTEGER

203

The returned metainformation in the entity-header is not the definitive set as available from the origin server, but is gathered from a local or a third-party copy.

HTTP_NO_CONTENT

PLS_INTEGER

204

The server has fulfilled the request but does not need to return an entity-body, and might want to return updated metainformation.

HTTP_RESET_CONTENT

PLS_INTEGER

205

The server has fulfilled the request and the user agent should reset the document view which caused the request to be sent. The response must not include an entity.

HTTP_PARTIAL_CONTENT

PLS_INTEGER

206

The server has fulfilled the partial GET request for the resource.

HTTP_MULTIPLE_CHOICES

PLS_INTEGER

300

The requested resource corresponds to any one of a set of representations, each with its own specific location, and agent- driven negotiation information is being provided so that the user (or user agent) can select a preferred representation and redirect its request to that location.

HTTP_MOVED_PERMANENTLY

PLS_INTEGER

301

The requested resource has been assigned a new permanent URI and any future references to this resource should use one of the returned URIs.

HTTP_FOUND CONSTANT

PLS_INTEGER

302

The requested resource resides temporarily under a different URI.

HTTP_SEE_OTHER

PLS_INTEGER

303

The response to the request can be found under a different URI and should be retrieved using a GET method on that resource.

HTTP_NOT_MODIFIED

PLS_INTEGER

304

If the client has performed a conditional GET request and access is allowed, but the document has not been modified, the server responds with this status code.

HTTP_USE_PROXY

PLS_INTEGER

305

The requested resource must be accessed through the proxy given by the Location field. The Location field gives the URI of the proxy.

HTTP_TEMPORARY_REDIRECT

PLS_INTEGER

307

The requested resource resides temporarily under a different URI.

HTTP_BAD_REQUEST

PLS_INTEGER

400

The request could not be understood by the server due to malformed syntax.

HTTP_UNAUTHORIZED

PLS_INTEGER

401

The request requires user authentication. The client may repeat the request with a suitable Authorization header field. If the request already included Authorization credentials, then the 401 response indicates that authorization has been refused for those credentials.

HTTP_PAYMENT_REQUIRED

PLS_INTEGER

402

This code is reserved for future use.

HTTP_FORBIDDEN

PLS_INTEGER

403

The server understood the request, but is refusing to fulfill it.

HTTP_NOT_FOUND

PLS_INTEGER

404

The server has not found anything matching the Request-URI.

HTTP_NOT_ACCEPTABLE

PLS_INTEGER

406

The resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headers sent in the request.

HTTP_PROXY_AUTH_REQUIRED

PLS_INTEGER

407

This code is similar to 401 (Unauthorized), but indicates that the client must first authenticate itself with the proxy.

HTTP_REQUEST_TIME_OUT

PLS_INTEGER

408

The client did not produce a request within the time that the server was prepared to wait.

HTTP_CONFLICT

PLS_INTEGER

409

The request could not be completed due to a conflict with the current state of the resource.

HTTP_GONE

PLS_INTEGER

410

The requested resource is no longer available at the server and no forwarding address is known.

HTTP_LENGTH_REQUIRED

PLS_INTEGER

411

The server refuses to accept the request without a defined Content-Length.

HTTP_PRECONDITION_FAILED

PLS_INTEGER

412

The precondition given in one or more of the request-header fields evaluated to false when it was tested on the server.

HTTP_REQUEST_ENTITY_TOO_LARGE CONSTANT

PLS_INTEGER

413

The server is refusing to process a request because the request entity is larger than the server is willing or able to process.

HTTP_REQUEST_URI_TOO_LARGE

PLS_INTEGER

414

The server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.

HTTP_UNSUPPORTED_MEDIA_TYPE

PLS_INTEGER

415

The server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.

HTTP_REQ_RANGE_NOT_SATISFIABLE

PLS_INTEGER

416

A server returns a response with this status code if a request included a Range request-header field, and none of the range-specifier values in this field overlap the current extent of the selected resource, and the request did not include an If-Range request-header field.

HTTP_EXPECTATION_FAILED

PLS_INTEGER

417

The expectation given in an Expect request-header field could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could not be met by the next-hop server.

HTTP_NOT_IMPLEMENTED

PLS_INTEGER

501

The server does not support the functionality required to fulfill the request.

HTTP_BAD_GATEWAY

PLS_INTEGER

502

The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to fulfill the request

HTTP_SERVICE_UNAVAILABLE

PLS_INTEGER

503

The server is currently unable to handle the request due to a temporary overloading or maintenance of the server.

HTTP_GATEWAY_TIME_OUT

PLS_INTEGER

504

The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI (for example, HTTP, FTP, LDAP) or some other auxiliary server (for example, DNS) it needed to access in attempting to complete the request.

HTTP_VERSION_NOT_SUPPORTED

PLS_INTEGER

505

The server does not support, or refuses to support, the HTTP protocol version that was used in the request message.

The URL of the HTTP request. It is set after the request is created by BEGIN_REQUEST.

method

The method to be performed on the resource identified by the URL. It is set after the request is created by BEGIN_REQUEST.

http_version

The HTTP protocol version used to send the request. It is set after the request is created by BEGIN_REQUEST.

Usage Notes

The information returned in REQ from the interface begin_request is for read only. Changing the field values in the record has no effect on the request.

There are other fields in REQ record type whose names begin with the prefix private_. The fields are private and are intended for use by implementation of the UTL_HTTP package. You should not modify the fields.

The status code returned by the Web server. It is a 3-digit integer that indicates the results of the HTTP request as handled by the Web server. It is set after the response is processed by GET_RESPONSE.

reason_phrase

The short textual message returned by the Web server that describe the status code. It gives a brief description of the results of the HTTP request as handled by the Web server. It is set after the response is processed by GET_RESPONSE.

http_version

The HTTP protocol version used in the HTTP response. It is set after the response is processed by GET_RESPONSE.

Usage Notes

The information returned in RESP from the interface GET_RESPONSE is read-only. There are other fields in the RESP record type whose names begin with the prefix private_. The fields are private and are intended for use by implementation of the UTL_HTTP package. You should not modify the fields.

COOKIE and COOKIE_TABLE Types

The COOKIE type is the PL/SQL record type that represents an HTTP cookie. The COOKIE_TABLE type is a PL/SQL index-by-table type that represents a collection of HTTP cookies.

Table 169-6 shows the fields for the COOKIE and COOKIE_TABLE record types.

Table 169-6 Fields of COOKIE and COOKIE_TABLE Type

Field

Description

name

The name of the HTTP cookie

value

The value of the cookie

domain

The domain for which the cookie is valid

expire

The time by which the cookie will expire

path

The subset of URLs to which the cookie applies

secure

Should the cookie be returned to the Web server using secured means only.

version

The version of the HTTP cookie specification the cookie conforms. This field is NULL for Netscape cookies.

comment

The comment that describes the intended use of the cookie. This field is NULL for Netscape cookies.

Usage Notes

PL/SQL programs do not usually examine or change the cookie information stored in the UTL_HTTP package. The cookies are maintained by the package transparently. They are maintained inside the UTL_HTTP package, and they last for the duration of the database session only. PL/SQL applications that require cookies to be maintained beyond the lifetime of a database session can read the cookies using GET_COOKIES, store them persistently in a database table, and re-store the cookies back in the package using ADD_COOKIES in the next database session. All the fields in the cookie record, except for the comment field, must be stored. Do not alter the cookie information, which can result in an application error in the Web server or compromise the security of the PL/SQL and the Web server applications. See "Retrieving and Restoring Cookies".

CONNECTION Type

Use the PL/SQL record type to represent the remote hosts and TCP/IP ports of a network connection that is kept persistent after an HTTP request is completed, according to the HTTP 1.1 protocol specification. The persistent network connection may be reused by a subsequent HTTP request to the same host and port. The subsequent HTTP request may be completed faster because the network connection latency is avoided. connection_table is a PL/SQL table of connection.

For a direct HTTP persistent connection to a Web server, the host and port fields contain the host name and TCP/IP port number of the Web server. The proxy_host and proxy_port fields are not set. For an HTTP persistent connection that was previously used to connect to a Web server using a proxy, the proxy_host and proxy_port fields contain the host name and TCP/IP port number of the proxy server. The host and port fields are not set, which indicates that the persistent connection, while connected to a proxy server, is not bound to any particular target Web server. An HTTP persistent connection to a proxy server can be used to access any target Web server that is using a proxy.

The SSL field indicates if Secured Socket Layer (SSL) is being used in an HTTP persistent connection. An HTTPS request is an HTTP request made over SSL. For an HTTPS (SSL) persistent connection connected using a proxy, the host and port fields contain the host name and TCP/IP port number of the target HTTPS Web server and the fields will always be set. An HTTPS persistent connection to an HTTPS Web server using a proxy server can only be reused to make another request to the same target Web server.

Interfaces that manipulate attributes and configurations of the UTL_HTTP package in the current session

SET_PROXY

GET_PROXY

SET_COOKIE_SUPPORT

GET_COOKIE_SUPPORT

SET_FOLLOW_REDIRECT

GET_FOLLOW_REDIRECT

SET_BODY_CHARSET

GET_BODY_CHARSET

SET_PERSISTENT_CONN_SUPPORT

GET_PERSISTENT_CONN_SUPPORT

SET_DETAILED_EXCP_SUPPORT

GET_DETAILED_EXCP_SUPPORT

SET_WALLET

SET_TRANSFER_TIMEOUT

GET_TRANSFER_TIMEOUT

Interfaces that retrieve the last detailed exception code and message UTL_HTTP package in the current session

GET_DETAILED_SQLCODE

GET_DETAILED_SQLERRM

NOTE:

Some of the request and response interfaces bear the same name as the interface that manipulates the attributes and configurations of the package in the current session. They are overloaded versions of the interface that manipulate a request or a response.

Simple HTTP Fetches

REQUEST and REQUEST_PIECES take a string uniform resource locator (URL), contact that site, and return the data (typically HTML) obtained from that site.

You should not expect REQUEST or REQUEST_PIECES to succeed in contacting a URL unless you can contact that URL by using a browser on the same machine (and with the same privileges, environment variables, and so on.)

If REQUEST or REQUEST_PIECES fails (for example, if it raises an exception, or if it returns an HTML-formatted error message, but you believe that the URL argument is correct), then try contacting that same URL with a browser to verify network availability from your machine. You may have a proxy server set in your browser that needs to be set with each REQUEST or REQUEST_PIECES call using the optional proxy parameter.

Note:

UTL_HTTP can also use environment variables to specify its proxy behavior. For example, on UNIX, setting the environment variable http_proxy to a URL uses that service as the proxy server for HTTP requests. Setting the environment variable no_proxy to a domain name does not use the HTTP proxy server for URLs in that domain. When the UTL_HTTP package is executed in the Oracle database server, the environment variables are the ones that are set when the database instance is started.

Session Settings

Session settings manipulate the configuration and default behavior of UTL_HTTP when HTTP requests are executed within a database user session. When a request is created, it inherits the default settings of the HTTP cookie support, follow-redirect, body character set, persistent-connection support, and transfer timeout of the current session. Those settings can be changed later by calling the request interface. When a response is created for a request, it inherits those settings from the request. Only the body character set can be changed later by calling the response interface.

HTTP Requests

The HTTP Requests group of subprograms begin an HTTP request, manipulate attributes, and send the request information to the Web server. When a request is created, it inherits the default settings of the HTTP cookie support, follow-redirect, body character set, persistent-connection support, and transfer timeout of the current session. The settings can be changed by calling the request interface.

HTTP Responses

The HTTP Responses group of subprograms manipulate an HTTP response obtained from GET_RESPONSE and receive response information from the Web server. When a response is created for a request, it inherits settings of the HTTP cookie support, follow-redirect, body character set, persistent-connection support, and transfer timeout from the request. Only the body character set can be changed by calling the response interface.

Error Conditions

Exceptions

Table 169-7 lists the exceptions that the UTL_HTTP package interface can raise. By default, UTL_HTTP raises the exception request_failed when a request fails to execute. If the package is set to raise a detailed exception by set_detailed_excp_support, the rest of the exceptions will be raised directly (except for the exception end_of_body, which will be raised by READ_TEXT, READ_LINE, and READ_RAW regardless of the setting).

Table 169-7 UTL_HTTP Exceptions

Exception

Error Code

Reason

Where Raised

REQUEST_FAILED

29273

The request fails to executes

Any HTTP request or response interface when detailed_exception is disabled

BAD_ARGUMENT

29261

The argument passed to the interface is bad

Any HTTP request or response interface when detailed_exception is enabled

BAD_URL

29262

The requested URL is badly formed

BEGIN_REQUEST, when detailed_exception is enabled

PROTOCOL_ERROR

29263

An HTTP protocol error occurs when communicating with the Web server

SET_HEADER, GET_RESPONSE, READ_RAW, READ_TEXT, and READ_LINE, when detailed_exception is enabled

UNKNOWN_SCHEME

29264

The scheme of the requested URL is unknown

BEGIN_REQUEST and GET_RESPONSE, when detailed_exception is enabled

HEADER_NOT_FOUND

29265

The header is not found

GET_HEADER, GET_HEADER_BY_NAME, when detailed_exception is enabled

END_OF_BODY

29266

The end of HTTP response body is reached

READ_RAW, READ_TEXT, and READ_LINE, when detailed_exception is enabled

ILLEGAL_CALL

29267

The call to UTL_HTTP is illegal at the current state of the HTTP request

SET_HEADER, SET_AUTHENTICATION, and SET_PERSISTENT_CONN_SUPPORT, when detailed_exception is enabled

HTTP_CLIENT_ERROR

29268

From GET_RESPONSE, the response status code indicates that a client error has occurred (status code in 4xx range). Or from begin_request, the HTTP proxy returns a status code in the 4xx range when making an HTTPS request through the proxy.

GET_RESPONSE, BEGIN_REQUEST when detailed_exception is enabled

HTTP_SERVER_ERROR

29269

From GET_RESPONSE, the response status code indicates that a client error has occurred (status code in 5xx range). Or from begin_request, the HTTP proxy returns a status code in the 5xx range when making an HTTPS request through the proxy.

GET_RESPONSE,BEGIN_REQUEST when detailed_exception is enabled

TOO_MANY_REQUESTS

29270

Too many requests or responses are open

BEGIN_REQUEST, when detailed_exception is enabled

PARTIAL_MULTIBYTE_EXCEPTION

29275

No complete character is read and a partial multibyte character is found at the end of the response body

READ_TEXT and READ_LINE, when detailed_exception is enabled

TRANSFER_TIMEOUT

29276

No data is read and a read timeout occurred

READ_TEXT and READ_LINE, when detailed_exception is enabled

NOTE:

The partial_multibyte_char and transfer_timeout exceptions are duplicates of the same exceptions defined in UTL_TCP. They are defined in this package so that the use of this package does not require the knowledge of the UTL_TCP. As those exceptions are duplicates, an exception handle that catches the partial_multibyte_char and transfer_timeout exceptions in this package also catch the exceptions in the UTL_TCP.

For REQUEST and REQUEST_PIECES, the request_failed exception is raised when any exception occurs and detailed_exception is disabled.

The cookies that the package currently maintains are not cleared before new cookies are added.

BEGIN_REQUEST Function

This functions begins a new HTTP request. UTL_HTTP establishes the network connection to the target Web server or the proxy server and sends the HTTP request line. The PL/SQL program continues the request by calling some other interface to complete the request. The URL may contain the username and password needed to authenticate the request to the server. The format is

The HTTP protocol version that sends the request. The format of the protocol version is HTTP/major-version.minor-version, where major-version and minor-version are positive numbers. If this parameter is set to NULL, UTL_HTTP uses the latest HTTP protocol version that it supports to send the request. The latest version that the package supports is 1.1 and it can be upgraded to a later version. The default is NULL.

Usage Notes

The URL passed as an argument to this function is not examined for illegal characters, such as spaces, according to URL specification RFC 2396. You should escape those characters with the UTL_URL package to return illegal and reserved characters. URLs should consist of US-ASCII characters only. See Chapter 180, "UTL_URL" for a list of legal characters in URLs. Note that URLs should consist of US-ASCII characters only. The use of non-US-ASCII characters in a URL is generally unsafe.

UTL_HTTP.BEGIN_REQUEST can send a URL whose length is up to 32767 bytes. However, different web servers impose different limits on the length of the URL they can accept. This limit is often about 4000 bytes. If this limit is exceeded, the outcome will depend on the web server. For example, a web server might simply drop the HTTP connection without returning a response of any kind. If this happens, a subsequent invocation of UTL_HTTP.GET_RESPONSE will raise the UTL_HTTP.PROTOCOL_ERROR exception.

A URL will be long when its QUERY_STRING (that is, the information that follows the question mark (?)) is long. In general, it is better to send this parameterization in the body of the request using the POST method.

CLOSE_PERSISTENT_CONNS Procedure

This procedure closes a group of HTTP persistent connections maintained by the UTL_HTTP package in the current database session. This procedure uses a pattern-match approach to decide which persistent connections to close.

To close a group of HTTP persistent connection that share a common property (for example, all connections to a particular host, or all SSL connections), set the particular parameters and leave the rest of the parameters NULL. If a particular parameter is set to NULL when this procedure is called, that parameter will not be used to decide which connections to close.

For example, the following call to the procedure closes all persistent connections to foobar:

UTL_HTTP.CLOSE_PERSISTENT_CONNS(host => 'foobar');

And the following call to the procedure closes all persistent connections through the proxy www-proxy at TCP/IP port 80:

Connections to the same Web server at different TCP/IP ports are counted individually. The host names of the Web servers are identified as specified in the URL of the original HTTP requests. Therefore, fully qualified host names with domain names will be counted differently from the host names without domain names.

Note that the use of a NULL value in a parameter when this procedure is called means that the caller does not care about its value when the package decides which persistent connection to close. If you want a NULL value in a parameter to match only a NULL value of the parameter of a persistent connection (which is when you want to close a specific persistent connection), you should use the CLOSE_PERSISTENT_CONN procedure that closes a specific persistent connection.

END_REQUEST Procedure

This procedure ends the HTTP request. To terminate the HTTP request without completing the request and waiting for the response, the program can call this procedure. Otherwise, the program should go through the normal sequence of beginning a request, getting the response, and closing the response. The network connection will always be closed and will not be reused.

Returns the HTTP authentication information required for the access to the HTTP proxy server instead of the Web server? Default is FALSE

Usage Notes

When a Web client is unaware that a document is protected, at least two HTTP requests are required for the document to be retrieved. In the first HTTP request, the Web client makes the request without supplying required authentication information; so the request is denied. The Web client can determine the authentication information required for the request to be authorized by calling GET_AUTHENTICATION. The Web client makes the second request and supplies the required authentication information with SET_AUTHORIZATION. If the authentication information can be verified by the Web server, the request will succeed and the requested document is returned. Before making the request, if the Web client knows that authentication information is required, it can supply the required authentication information in the first request, thus saving an extra request.

GET_BODY_CHARSET Procedure

This procedure retrieves the default character set of the body of all future HTTP requests.

GET_HEADER Procedure

UTL_HTTP.GET_HEADER (
r IN OUT NOCOPY resp,
n IN PLS_INTEGER,
name OUT NOCOPY VARCHAR2,
value OUT NOCOPY VARCHAR2);

Parameters

Table 169-28 GET_HEADER Procedure Parameters

Parameter

Description

r

The HTTP response

n

The nth header to return

name

The name of the HTTP response header

value

The value of the HTTP response header

Usage Notes

If the response body returned by the remote Web server is encoded in chunked transfer encoding format, the trailer headers that are returned at the end of the response body will be added to the response, and the response header count will be updated. You can retrieve the additional headers after the end of the response body is reached and before you end the response.

GET_HEADER_BY_NAME Procedure

This procedure returns the HTTP response header value returned in the response given the name of the header.

UTL_HTTP.GET_HEADER_BY_NAME(
r IN OUT NOCOPY resp,
name IN VARCHAR2,
value OUT NOCOPY VARCHAR2,
n IN PLS_INTEGER DEFAULT 1);

Parameters

Table 169-29 GET_HEADER_BY_NAME Procedure Parameters

Parameter

Description

r

The HTTP response

name

The name of the HTTP response header for which the value is to return

value

The value of the HTTP response header

n

The nth occurrence of an HTTP response header by the specified name to return. The default is 1.

Usage Notes

If the response body returned by the remote Web server is encoded in chunked transfer encoding format, the trailer headers that are returned at the end of the response body will be added to the response, and the response header count will be updated. You can retrieve the additional headers after the end of the response body is reached and before you end the response.

GET_HEADER_COUNT Function

This function returns the number of HTTP response headers returned in the response.

If the response body returned by the remote Web server is encoded in chunked transfer encoding format, the trailer headers that are returned at the end of the response body will be added to the response, and the response header count will be updated. You can retrieve the additional headers after the end of the response body is reached and before you end the response.

GET_PERSISTENT_CONN_COUNT Function

This function returns the number of network connections currently kept persistent by the UTL_HTTP package to the Web servers.

Connections to the same Web server at different TCP/IP ports are counted individually. The host names of the Web servers are identified as specified in the URL of the original HTTP requests. Therefore, fully qualified host names with domain names will be counted differently from the host names without domain names.

GET_PERSISTENT_CONN_SUPPORT Procedure

This procedure checks:

If the persistent connection support is enabled

Gets the maximum number of persistent connections in the current session

Connections to the same Web server at different TCP/IP ports are counted individually. The host names of the Web servers are identified as specified in the URL of the original HTTP requests. Therefore, fully qualified host names with domain names will be counted differently from the host names without domain names.

The proxy (host and an optional port number) currently used by the UTL_HTTP package

no_proxy_domains

The list of hosts and domains for which no proxy is used for all requests

GET_RESPONSE Function

This function reads the HTTP response. When the function returns, the status line and the HTTP response headers have been read and processed. The status code, reason phrase, and the HTTP protocol version are stored in the response record. This function completes the HTTP headers section.

READ_LINE Procedure

This procedure reads the HTTP response body in text form until the end of line is reached and returns the output in the caller-supplied buffer. The end of line is as defined in the function read_line of UTL_TCP. The end_of_body exception will be raised if the end of the HTTP response body is reached. Text data is automatically converted from the response body character set to the database character set.

UTL_HTTP.READ_LINE(
r IN OUT NOCOPY resp,
data OUT NOCOPY VARCHAR2 CHARACTER SET ANY_CS,
remove_crlf IN BOOLEAN DEFAULT FALSE);

Parameters

Table 169-37 READ_LINE Procedure Parameters

Parameter

Description

r

The HTTP response

data

The HTTP response body in text form

remove_crlf

Removes the newline characters if set to TRUE

Usage Notes

The UTL_HTTP package supports HTTP 1.1 chunked transfer-encoding. When the response body is returned in chunked transfer-encoding format as indicated in the response header, the package automatically decodes the chunks and returns the response body in de-chunked format.

If transfer timeout is set in the request of this response, read_line waits for each data packet to be ready to read until timeout occurs. If it occurs, this procedure stops reading and returns all the data read successfully. If no data is read successfully, the transfer_timeout exception is raised. The exception can be handled and the read operation can be retried later.

If a partial multibyte character is found at the end of the response body, read_line stops reading and returns all the complete multibyte characters read successfully. If no complete character is read successfully, the partial_multibyte_char exception is raised. The exception can be handled and the bytes of that partial multibyte character can be read as binary by the read_raw procedure. If a partial multibyte character is seen in the middle of the response body because the remaining bytes of the character have not arrived and read timeout occurs, the transfer_timeout exception is raised instead. The exception can be handled and the read operation can be retried later.

When the "Content-Type" response header specifies the character set of the response body and the character set is unknown or unsupported by Oracle, the "ORA-01482: unsupported character set" exception is raised if you try to read the response body as text. You can either read the response body as binary using the READ_RAW procedure, or set the character set of the response body explicitly using the SET_BODY_CHARSET procedure and read the response body as text again.

READ_RAW Procedure

This procedure reads the HTTP response body in binary form and returns the output in the caller-supplied buffer. The end_of_body exception will be raised if the end of the HTTP response body is reached.

The number of bytes of data to read. If len is NULL, this procedure will read as much input as possible to fill the buffer allocated in data. The actual amount of data returned may be less than that specified if not much data is available before the end of the HTTP response body is reached or the transfer_timeout amount of time has elapsed. The default is NULL

Usage Notes

The UTL_HTTP package supports HTTP 1.1 chunked transfer-encoding. When the response body is returned in chunked transfer-encoding format as indicated in the response header, the package automatically decodes the chunks and returns the response body in de-chunked format.

If transfer timeout is set in the request of this response, read_raw waits for each data packet to be ready to read until timeout occurs. If it occurs, read_raw stops reading and returns all the data read successfully. If no data is read successfully, the transfer_timeout exception is raised. The exception can be handled and the read operation can be retried later.

READ_TEXT Procedure

This procedure reads the HTTP response body in text form and returns the output in the caller-supplied buffer. The end_of_body exception will be raised if the end of the HTTP response body is reached. Text data is automatically converted from the response body character set to the database character set.

UTL_HTTP.READ_TEXT(
r IN OUT NOCOPY resp,
data OUT NOCOPY VARCHAR2 CHARACTER SET ANY_CS,
len IN PLS_INTEGER DEFAULT NULL);

Parameters

Table 169-39 READ_TEXT Procedure Parameters

Parameter

Description

r

The HTTP response

data

The HTTP response body in text form

len

The maximum number of characters of data to read. If len is NULL, this procedure will read as much input as possible to fill the buffer allocated in data. The actual amount of data returned may be less than that specified if little data is available before the end of the HTTP response body is reached or the transfer_timeout amount of time has elapsed. The default is NULL.

Usage Notes

The UTL_HTTP package supports HTTP 1.1 chunked transfer-encoding. When the response body is returned in chunked transfer-encoding format as indicated in the response header, the package automatically decodes the chunks and returns the response body in de-chunked format.

If transfer timeout is set in the request of this response, read_text waits for each data packet to be ready to read until timeout occurs. If it occurs, this procedure stops reading and returns all the data read successfully. If no data is read successfully, the transfer_timeout exception is raised. The exception can be handled and the read operation can be retried later.

If a partial multibyte character is found at the end of the response body, read_text stops reading and returns all the complete multibyte characters read successfully. If no complete character is read successfully, the partial_multibyte_char exception is raised. The exception can be handled and the bytes of that partial multibyte character can be read as binary by the read_raw procedure. If a partial multibyte character is seen in the middle of the response body because the remaining bytes of the character have not arrived and read timeout occurs, the transfer_timeout exception is raised instead. The exception can be handled and the read operation can be retried later.

When the "Content-Type" response header specifies the character set of the response body and the character set is unknown or unsupported by Oracle, the "ORA-01482: unsupported character set" exception is raised if you try to read the response body as text. You can either read the response body as binary using the READ_RAW procedure, or set the character set of the response body explicitly using the SET_BODY_CHARSET procedure and read the response body as text again.

REQUEST Function

This function returns up to the first 2000 bytes of data retrieved from the given URL. This function can be used directly in SQL queries. The URL may contain the username and password needed to authenticate the request to the server. The format is

scheme://[user[:password]@]host[:port]/[...]

You can define a username/password for the proxy to be specified in the proxy string. The format is

(Optional) Specifies a proxy server to use when making the HTTP request. See SET_PROXY for the full format of the proxy setting.

wallet_path

(Optional) Specifies a client-side wallet. The client-side wallet contains the list of trusted certificate authorities required for HTTPS request. The format of wallet_path on a PC is, for example, file:c:\WINNT\Profiles\<username>\WALLETS, and in Unix is, for example, file:/home/<username>/wallets

When the UTL_HTTP package is executed in the Oracle database server, the wallet is accessed from the database server. Therefore, the wallet path must be accessible from the database server. See SET_WALLET for a description on how to set up an Oracle wallet. Non-HTTPS requests do not require an Oracle wallet.

wallet_password

(Optional) Specifies the password required to open the wallet

Return Values

The return type is a string of length 2000 or less, which contains up to the first 2000 bytes of the HTML result returned from the HTTP request to the argument URL.

Exceptions

INIT_FAILED
REQUEST_FAILED

Usage Notes

The URL passed as an argument to this function is not examined for illegal characters, for example, spaces, according to URL specification RFC 2396. The caller should escape those characters with the UTL_URL package. See the comments of the package for the list of legal characters in URLs. Note that URLs should consist of US-ASCII characters only. The use of non-US-ASCII characters in a URL is generally unsafe.

Please see the documentation of the function SET_WALLET on the use of an Oracle wallet, which is required for accessing HTTPS Web servers.

Unless response error check is turned on, this function does not raise an exception when a 4xx or 5xx response is received from the Web server. Instead, it returns the formatted error message from the Web server:

(Optional) The maximum number of pieces (each 2000 characters in length, except for the last, which may be shorter), that REQUEST_PIECES should return. If provided, then that argument should be a positive integer.

proxy

(Optional) Specifies a proxy server to use when making the HTTP request. See SET_PROXY for the full format of the proxy setting.

The format of wallet_path on a PC is, for example, file:c:\WINNT\Profiles\<username>\WALLETS, and in Unix is, for example, file:/home/<username>/wallets. When the UTL_HTTP package is executed in the Oracle database server, the wallet is accessed from the database server. Therefore, the wallet path must be accessible from the database server.

See SET_WALLET for the description on how to set up an Oracle wallet. Non-HTTPS requests do not require an Oracle wallet.

wallet_password

(Optional) Specifies the password required to open the wallet

Return Values

REQUEST_PIECES returns a PL/SQL table of type UTL_HTTP.HTML_PIECES. Each element of that PL/SQL table is a string of maximum length 2000. The elements of the PL/SQL table returned by REQUEST_PIECES are successive pieces of the data obtained from the HTTP request to that URL.

Exceptions

INIT_FAILED
REQUEST_FAILED

Usage Notes

The URL passed as an argument to this function will not be examined for illegal characters, for example, spaces, according to URL specification RFC 2396. The caller should escape those characters with the UTL_URL package. See the comments of the package for the list of legal characters in URLs. Note that URLs should consist of US-ASCII characters only. The use of non-US-ASCII characters in a URL is generally unsafe.

Each entry of the PL/SQL table (the "pieces") returned by this function may not be filled to their fullest capacity. The function may start filling the data in the next piece before the previous "piece" is totally full.

Please see the documentation of the function SET_WALLET on the use of an Oracle wallet, which is required for accessing HTTPS Web servers.

Unless response error check is turned on, this function does not raise an exception when a 4xx or 5xx response is received from the Web server. Instead, it returns the formatted error message from the Web server:

Sets the default character set of the body of all future HTTP requests when the media type is text and the character set is not specified in the Content-Type header. Following the HTTP protocol standard specification, if the media type of a request or a response is text, but the character set information is missing in the Content-Type header, the character set of the request or response body should default to ISO-8859-1. A response created for a request inherits the default body character set of the request instead of the body character set of the current session. The default body character set is ISO-8859-1 in a database user session. The default body character set setting affects only future requests and has no effect on existing requests. After a request is created, the body character set can be changed by using the other SET_BODY_CHARSET procedure that operates on a request:

UTL_HTTP.SET_BODY_CHARSET (
charset IN VARCHAR2 DEFAULT NULL);

Sets the character set of the request body when the media type is text but the character set is not specified in the Content-Type header. According to the HTTP protocol standard specification, if the media type of a request or a response is "text" but the character set information is missing in the Content-Type header, the character set of the request or response body should default to "ISO-8859-1". Use this procedure to change the default body character set a request inherits from the session default setting:

Sets the character set of the response body when the media type is "text" but the character set is not specified in the "Content-Type" header. For each the HTTP protocol standard specification, if the media type of a request or a response is "text" but the character set information is missing in the "Content-Type" header, the character set of the request or response body should default to "ISO-8859-1". Use this procedure to change the default body character set a response inherits from the request:

The default character set of the response body. The character set can be in Oracle or Internet Assigned Numbers Authority (IANA) naming convention. If charset is NULL, the database character set is assumed.

SET_COOKIE_SUPPORT Procedures

This procedure is overloaded. The description of different functionality is located alongside the syntax declarations.

Sets the maximum total number of cookies maintained in the current session

max_cookies_per_site

Sets the maximum number of cookies maintained in the current session for each Web site

Usage Notes

If cookie support is enabled for an HTTP request, all cookies saved in the current session and applicable to the request are returned to the Web server in the request in accordance with HTTP cookie specification standards. Cookies set in the response to the request are saved in the current session for return to the Web server in the subsequent requests if cookie support is enabled for those requests. If the cookie support is disabled for an HTTP request, no cookies are returned to the Web server in the request and the cookies set in the response to the request are not saved in the current session, although the Set-Cookie HTTP headers can still be retrieved from the response.

Cookie support is enabled by default for all HTTP requests in a database user session. The default setting of the cookie support (enabled versus disabled) affects only the future requests and has no effect on the existing ones. After your request is created, the cookie support setting may be changed by using the other SET_COOKIE_SUPPORT procedure that operates on a request.

The default maximum number of cookies saved in the current session is 20 for each site and 300 total.

If you lower the maximum total number of cookies or the maximum number of cookies for each Web site, the oldest cookies will be purged first to reduce the number of cookies to the lowered maximum. HTTP cookies saved in the current session last for the duration of the database session only; there is no persistent storage for the cookies. Cookies saved in the current session are not cleared if you disable cookie support.

See "Examples" for how to use GET_COOKIES and ADD_COOKIES to retrieve, save, and restore cookies.

SET_DETAILED_EXCP_SUPPORT Procedure

This procedure sets the UTL_HTTP package to raise a detailed exception. By default, UTL_HTTP raises the request_failed exception when an HTTP request fails. Use GET_DETAILED_SQLCODE and GET_DETAILED_SQLEERM for more detailed information about the error.

If max_redirects is set to a positive number, the GET_RESPONSE Function will automatically follow the redirected URL for the HTTP response status code 301, 302, and 307 for the HTTP HEAD and GET methods, and 303 for all HTTP methods, and retry the HTTP request (the request method will be changed to HTTP GET for the status code 303) at the new location. It follows the redirection until the final, non-redirect location is reached, or an error occurs, or the maximum number of redirections has been reached (to prevent an infinite loop). The URL and method fields in the REQ record will be updated to the last redirected URL and the method used to access the URL. Set the maximum number of redirects to zero to disable automatic redirection.

While it is set not to follow redirect automatically in the current session, it is possible to specify individual HTTP requests to follow redirect instructions the function FOLLOW_REDIRECT and vice versa.

The default maximum number of redirections in a database user session is 3. The default value affects only future requests and has no effect on existing requests.

The SET_FOLLOW_REDIRECT procedure must be called before GET_RESPONSE for any redirection to take effect.

SET_HEADER Procedure

This procedure sets an HTTP request header. The request header is sent to the Web server as soon as it is set.

UTL_HTTP.SET_HEADER (
r IN OUT NOCOPY req,
name IN VARCHAR2,
value IN VARCHAR2);

Parameters

Table 169-47 SET_HEADER Procedure Parameters

Parameter

Description

r

The HTTP request

name

The name of the HTTP request header

value

The value of the HTTP request header

Usage Notes

Multiple HTTP headers with the same name are allowed in the HTTP protocol standard. Therefore, setting a header does not replace a prior header with the same name.

If the request is made using HTTP 1.1, UTL_HTTP sets the Host header automatically for you.

When you set the Content-Type header with this procedure, UTL_HTTP looks for the character set information in the header value. If the character set information is present, it is set as the character set of the request body. It can be overridden later by using the SET_BODY_CHARSET procedure.

When you set the Transfer-Encoding header with the value chunked,UTL_HTTP automatically encodes the request body written by the WRITE_TEXT, WRITE_LINE and WRITE_RAWprocedures. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format.

SET_PERSISTENT_CONN_SUPPORT Procedure

This procedure enables or disables support for the HTTP 1.1 persistent-connection in the request.

If the persistent-connection support is enabled for an HTTP request, the package will keep the network connections to a Web server or the proxy server open in the package after the request is completed properly for a subsequent request to the same server to reuse for each HTTP 1.1 protocol specification. With the persistent connection support, subsequent HTTP requests may be completed faster because the network connection latency is avoided. If the persistent-connection support is disabled for a request, the package will always send the HTTP header "Connection: close" automatically in the HTTP request and close the network connection when the request is completed. This setting has no effect on HTTP requests that follows HTTP 1.0 protocol, for which the network connections will always be closed after the requests are completed.

When a request is being made, the package attempts to reuse an existing persistent connection to the target Web server (or proxy server) if one is available. If none is available, a new network connection will be initiated. The persistent-connection support setting for a request affects only whether the network connection should be closed after a request completes.

Use this procedure to change the persistent-connection support setting a request inherits from the session default setting.

Users should note that while the use of persistent connections in UTL_HTTP may reduce the time it takes to fetch multiple Web pages from the same server, it consumes precious system resources (network connections) in the database server. Also, excessive use of persistent connections may reduce the scalability of the database server when too many network connections are kept open in the database server. Network connections should be kept open only if they will be used immediately by subsequent requests and should be closed immediately when they are no longer needed. Set the default persistent connection support as disabled in the session, and enable persistent connection in individual HTTP requests as shown in "Examples".

The default value of the maximum number of persistent connections in a database session is zero. To truly enable persistent connections, you must also set the maximum number of persistent connections to a positive value or no connections will be kept persistent.

SET_PROXY Procedure

This procedure sets the proxy to be used for requests of the HTTP or other protocols, excluding those for hosts that belong to the domain specified in no_proxy_domains.no_proxy_domains is a comma-, semi-colon-, or space-separated list of domains or hosts for which HTTP requests should be sent directly to the destination HTTP server instead of going through a proxy server.

The proxy (host and an optional port number) to be used by the UTL_HTTP package

no_proxy_domains

The list of hosts and domains for which no proxy should be used for all requests

Usage Notes

The proxy may include an optional TCP/IP port number at which the proxy server listens. The syntax is [http://]host[:port][/], for example, www-proxy.my-company.com:80. If the port is not specified for the proxy, port 80 is assumed.

Optionally, a port number can be specified for each domain or host. If the port number is specified, the no-proxy restriction is only applied to the request at the port of the particular domain or host, for example, corp.my-company.com, eng.my-company.com:80. When no_proxy_domains is NULL and the proxy is set, all requests go through the proxy. When the proxy is not set, UTL_HTTP sends requests to the target Web servers directly.

You can define a username/password for the proxy to be specified in the proxy string. The format is

[http://][user[:password]@]host[:port][/]

If proxy settings are set when the database server instance is started, the proxy settings in the environment variables http_proxy and no_proxy are assumed. Proxy settings set by this procedure override the initial settings.

SET_RESPONSE_ERROR_CHECK Procedure

This procedure sets whether or not GET_RESPONSE raises an exception when the Web server returns a status code that indicates an error—a status code in the 4xx or 5xx ranges. For example, when the requested URL is not found in the destination Web server, a 404 (document not found) response status code is returned.

If the status code indicates an error—a 4xx or 5xx code—and this procedure is enabled, GET_RESPONSE will raise the HTTP_CLIENT_ERROR or HTTP_SERVER_ERROR exception. If SET_RESPONSE_ERROR_CHECK is set to FALSE, GET_RESPONSE will not raise an exception when the status code indicates an error.

Response error check is turned off by default.

The GET_RESPONSE function can raise other exceptions when SET_RESPONSE_ERROR_CHECK is set to FALSE.

SET_TRANSFER_TIMEOUT Procedure

This procedure sets the default time out value for all future HTTP requests that the UTL_HTTP package should attempt while reading the HTTP response from the Web server or proxy server. This time out value may be used to avoid the PL/SQL programs from being blocked by busy Web servers or heavy network traffic while retrieving Web pages from the Web servers.

SET_WALLET Procedure

This procedure sets the Oracle wallet used for all HTTP requests over Secured Socket Layer (SSL), namely HTTPS. When the UTL_HTTP package communicates with an HTTP server over SSL, the HTTP server presents its digital certificate, which is signed by a certificate authority, to the UTL_HTTP package for identification purpose. The Oracle wallet contains the list of certificate authorities that are trusted by the user of the UTL_HTTP package. An Oracle wallet is required to make an HTTPS request.

The directory path that contains the Oracle wallet. The format is file:<directory-path>.

The format of wallet_path on a PC is, for example, file:c:\WINNT\Profiles\<username>\WALLETS, and in Unix is, for example, file:/home/<username>/wallets. When the UTL_HTTP package is executed in the Oracle database server, the wallet is accessed from the database server. Therefore, the wallet path must be accessible from the database server.

password

The password needed to open the wallet. A second copy of a wallet in a wallet directory that may be opened without a password. That second copy of the wallet is read-only. If the password is NULL, the UTL_HTTP package will open the second, read-only copy of the wallet instead.

Usage Notes

To set up an Oracle wallet, use the Oracle Wallet Manager to create a wallet. In order for the HTTPS request to succeed, the certificate authority that signs the certificate of the remote HTTPS Web server must be a trust point set in the wallet.

When a wallet is created, it is populated with a set of well-known certificate authorities as trust points. If the certificate authority that signs the certificate of the remote HTTPS Web server is not among the trust points, or the certificate authority has new root certificates, you should obtain the root certificate of that certificate authority and install it as a trust point in the wallet using Oracle Wallet Manager

WRITE_LINE Procedure

This procedure writes a text line in the HTTP request body and ends the line with new-line characters (CRLF as defined in UTL_TCP). As soon as some data is sent as the HTTP request body, the HTTP request headers section is completed. Text data is automatically converted from the database character set to the request body character set.

UTL_HTTP.WRITE_LINE(
r IN OUT NOCOPY req,
data IN VARCHAR2 CHARACTER SET ANY_CS);

Parameters

Table 169-53 WRITE_LINE Procedure Parameters

Parameter

Description

r

The HTTP request

data

The text line to send in the HTTP request body

Usage Notes

An HTTP client must always let the remote Web server know the length of the request body it is sending. If the amount of data is known beforehand, you can set the Content-Length header in the request, where the length of the content is measured in bytes instead of characters. If the length of the request body is not known beforehand, you can send the request body using the HTTP 1.1 chunked transfer-encoding format. The request body is sent in chunks, where the length of each chunk is sent before the chunk is sent. The UTL_HTTP package performs chunked transfer-encoding on the request body transparently when the Transfer-Encoding: chunked header is set. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format. See the SET_HEADER procedure for details.

If you send the Content-Length header, you should note that the length specified in the header should be the byte-length of the textual request body after it is converted from the database character set to the request body character set. When either one of the two character sets is a multibyte character set, the precise byte-length of the request body in the request body character set cannot be known beforehand. In this case, you can perform the character set conversion explicitly, determine the byte-length of the results, send the Content-Length header, and the results using the WRITE_RAW procedure to avoid the automatic character set conversion. Or, if the remove Web server or CGI programs allow, you can send the request body using the HTTP 1.1 chunked transfer-encoding format, where UTL_HTTP handles the length of the chunks transparently.

WRITE_RAW Procedure

This procedure writes some binary data in the HTTP request body. As soon as some data is sent as the HTTP request body, the HTTP request headers section is completed.

An HTTP client must always let the remote Web server know the length of the request body it is sending. If the amount of data is known beforehand, you can set the Content-Length header in the request, where the length of the content is measured in bytes instead of characters. If the length of the request body is not known beforehand, you can send the request body using the HTTP 1.1 chunked transfer-encoding format. The request body is sent in chunks, where the length of each chunk is sent before the chunk is sent. UTL_HTTP performs chunked transfer-encoding on the request body transparently when the Transfer-Encoding:chunked header is set. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format. See the SET_HEADER procedure for details.

WRITE_TEXT Procedure

This procedure writes some text data in the HTTP request body. As soon as some data is sent as the HTTP request body, the HTTP request headers section is completed. Text data is automatically converted from the database character set to the request body character set.

UTL_HTTP.WRITE_TEXT(
r IN OUT NOCOPY REQ,
data IN VARCHAR2 CHARACTER SET ANY_CS);

Parameters

Table 169-55 WRITE_TEXT Procedure Parameters

Parameter

Description

r

The HTTP request

data

The text data to send in the HTTP request body

Usage Notes

An HTTP client must always let the remote Web server know the length of the request body it is sending. If the amount of data is known beforehand, you can set the Content-Length header in the request, where the length of the content is measured in bytes instead of characters. If the length of the request body is not known beforehand, you can send the request body using the HTTP 1.1 chunked transfer-encoding format. The request body is sent in chunks, where the length of each chunk is sent before the chunk is sent. UTL_HTTP performs chunked transfer-encoding on the request body transparently when the Transfer-Encoding: chunked header is set. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format. See the SET_HEADER procedure for details.

If you send the Content-Length header, you should note that the length specified in the header should be the byte-length of the textual request body after it is converted from the database character set to the request body character set. When either one of the two character sets is a multibyte character set, the precise byte-length of the request body in the request body character set cannot be known beforehand. In this case, you can perform the character set conversion explicitly, determine the byte-length of the results, send the Content-Length header, and the results using the WRITE_RAW procedure to avoid the automatic character set conversion. Or, if the remove Web server or CGI programs allow, you can send the request body using the HTTP 1.1 chunked transfer-encoding format, where UTL_HTTP handles the length of the chunks transparently.

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